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3 years ago

The molar mass of a certain gas is 80.6 g. What is the density of the gas in g/L at STP?

1 answer:

3 0

Using the ideal gas equation:
PV = nRT

Substituting n with mass / Mr
PV = mRT/Mr

Density = m/V
So rearranging:
Density = PMr/RT

P = 1 atm
R = 0.082 L atm / K mol
T = 273 K
Density = (1 x 80.6) / (0.082 x 273)
Density = 3.6 g / L

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Consider the following reaction: A(g)⇌2B(g). Find the equilibrium partial pressures of A and B for each of the following differe

Illusion [34]

Answer:

a. Kp=1.4

$P_{A}=0.2215 atm$

$P_{B}=0.556 atm$

b.Kp=2.0 * 10^-4

$P_{A}=0.495atm$

$P_{B}=0.00995 atm$

c.Kp=2.0 * 10^5

$P_{A}=5*10^{-6}atm$

$P_{B}=0.9999 atm$

Explanation:

For the reaction

A(g)⇌2B(g)

Kp is defined as:

$Kp=\frac{(P_{B})^{2}}{P_{A}}$

The conditions in the system are:

A B

initial 0 1 atm

equilibrium x 1atm-2x

At the beginning, we don’t have any A in the system, so B starts to react to produce A until the system reaches the equilibrium producing x amount of A. From the stoichiometric relationship in the reaction we get that to produce x amount of A we need to 2x amount of B so in the equilibrium we will have 1 atm – 2x of B, as it is showed in the table.

Replacing these values in the expression for Kp we get:

$Kp=\frac{(1-2x)^{2}}{x}$

Working with this equation:

$x*Kp=(1-2x)^{2} - -> x*Kp=4x^{2}-4x+1- - >4x^{2}-(4+Kp)*x+1=0$

This last expression is quadratic expression with a=4, b=-(4+Kp) and c=1

The general expression to solve these kinds of equations is:

$x=\frac{-b(+-)*\sqrt{(b^{2}-4ac)}}{2a}$ (equation 1)

We just take the positive values from the solution since negative partial pressures don´t make physical sense.

Kp = 1.4

$x_{1}=\frac{(1.4+4)+\sqrt{(-(1.4+4)^{2}-4*4*1)}}{2*4}=1.128$

$x_{1}=\frac{(1.4+4)-\sqrt{(-(1.4+4)^{2}-4*4*1)}}{2*4}=0.2215$

With x1 we get a partial pressure of:

$P_{A}=1.128 atm$

$P_{B}=1-2*1.128 = -1.256 atm$

Since negative partial pressure don´t make physical sense x1 is not the solution for the system.

With x2 we get:

$P_{A}=0.2215 atm$

$P_{B}=1-2*0.2215 = 0.556 atm$

These partial pressures make sense so x2 is the solution for the equation.

We follow the same analysis for the other values of Kp.

Kp=2*10^-4

X1=0.505

X2=0.495

With x1

$P_{A}=0.505atm$

$P_{B}=1-2*0.505 = -0.01005 atm$

Not sense.

With x2

$P_{A}=0.495atm$

$P_{B}=1-2*0.495 = 0.00995 atm$

X2 is the solution for this equation.

Kp=2*10^5

X1=50001

$X2=5*10^{-6}$

With x1

$P_{A}=50001atm$

$P_{B}=1-2*50001=-100001atm$

Not sense.

With x2

$P_{A}= 5*10^{-6}atm$

$P_{B}=1-2*5*10^{-6}= 0.9999 atm$

X2 is the solution for this equation.

8 0

4 years ago

The weight of an object is constant. true false

Dahasolnce [82]

False weight is dependent on the force of gravity

8 0

3 years ago

Read 2 more answers

Which statement best describes visible light?

tekilochka [14]

Answer:

The Visible Spectrum Visible light is the light that we can see, and thus is the only light detectable by the human eye. White light is visible light, and it contains all the colors of the rainbow, from red to violet. The range of visible wavelengths is 400 to 700 nanometers.

Explanation:

6 0

3 years ago

Nitrous oxide gas is a form of

zepelin [54]

Its a form of anaesthesia used by dentists

hope that helsp

6 0

3 years ago

To determine the concentration of an EDTA solution, 4.11 g of Zn metal was used. The volume of EDTA solution needed to reach the

USPshnik [31]

Answer:

2.23M

Explanation:

Molarity of a solution is calculated thus

Molarity = number of moles (n) ÷ volume (V)

According to this question, 4.11g of Zn metal was used in order to reach a volume of EDTA solution of 28.26 mL.

28.26mL = 28.26/1000

= 0.02826L

Using mole = mass/molar mass to calculate no. of moles of Zn

Mole = 4.11/65.4

mole = 0.0628mol

Molarity = 0.0628 ÷ 0.02826

Molarity = 2.23M

The concentration of the EDTA solution used is 2.23M

7 0

3 years ago